German tuner Vath set their sites on a the CL550 and in the process designed an upgraded camshaft package and tune for the M273 V8. Stock power is 388 horsepower but Vath increases output by 72 horses with aftermarket cams, sport cats, and a tune. That gets the car close to a stock M156 so those who did not opt for the say the CL63, ML63, or SL63 AMG have a nice upgrade naturally aspirated upgrade path if they desire.

I'm not really sure to be honest if they just resell Schrick cams or not since i don't know much about Vath. But that's what all BMW tuners do.
But the chances are big. i know no other cam suppliers than Schrick in Germans aftermarket.